US2971511A - Cellulosic product - Google Patents

Description

6 K. J. HARWOOD CELLULOSIC PRODUCT Filed Jan. 13, 1958 CELLULOSIC PRODUCT Kenneth J. Harwood, Neenah, Wis, assignor to Kimberly- Clark Corporation, Neenah, Wis, a corporation of Delaware Filed Jan. 13, 1958, Ser. No. 708,672

2 Claims. (Cl. 128-290) This invention relates to improvements in sanitary napkins.

To provide the intended function, it is essential that a sanitary napkin have an unusually high degree of fluid absorbency. In order that this high degree of absorbency may be achieved without strike-through of fluid to the outermost surface of the napkin or pad with consequent staining of garments which may come in contact with that surface, it is preferable that the napkin have means such as battles to spread the flow of fluid to a large portion of the napkin so that the absorptive potential of the napkin can be utilized. a

To achieve these objects in the most desirable manner, it has been found advantageous to employ in the body of the napkin a variety of materials in a planned arrangement. For example, a current type of sanitary napkin includes in its body portion top and bottom layers of creped tissue paper and intermediate layers of fluffy wood cellulose and a fiber bat of cotton, rayon or the like with which are combined suitable bafiles of lightly waxed tissue paper, to spread the flow of fluid for maximum absorption;

To achieve maximum absorbency in a napkin of the above-described type, with minimum opportunity for the fluid to strike-through the pad and without excessive bulk, the main part of the absorbent material is arranged to the side of the napkin which will be worn next to the body. That is, the various layers or plies of material are arranged so that the absorbent materi-al tends to be grouped to one surface of the pad while other elements such as baffles will be positioned at or close to the other surface. The result, of course, is a non-symmetrical napkin particularly adapted to be worn with one surface or side toward the body and the reverse surface away from the body. However, it is also desirable that this special arrangement not be carried to the point where unsatisfactory performance in the way of absorption will result if the napkin is mistakenly worn with the reverse side adjacent to the body, as may rather frequently occur.

The various plies or layers making up the body portion of the napkin commonly are secured together by an outer wrapper of gauze or similar porous material, the seam of which extends longitudinally of the napkin. It is desirable that this seam be arranged to lie on the surface of the body portion intended to be worn away from the body, primarily for the reason that although the wrapper consists of unusually soft material, the raw edge of the wrapper at the scam in certain cases has a tendency to cause irritation of the body.

In use, it is preferred that the relatively flat napkin be folded around a longitudinal center line into a substantially U-shape configuration, with the base of the U being applied against the body. With this arrangement, the napkin provides the maximum absorbency with the greatest comfort and ease of application, and with minimum danger of menstrual fluid striking through the napkin to the clothing. Unless a sanitary pad is properly positioned on the body there is a tendency for the body fluid to overflow the pad,

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with resultant discomfort, embarrassment and inconvenrence.

It is the purpose of this invention to provide a sanitary napkin or pad incorporating means which will assist in the folding of the napkin along a longitudinal center line and in a manner so that there will be exposed for application directly against the body that surface of the napkin which will permit the napkin to give maximum protection and comfort to the wearer. Furthermore, this means also permits easy detection of the side of the pad to be worn away from the body. This and other objects and advantages of the invention will be readily undertsood from the following description and appended drawings, in which:

Figure 1 is a cross-section, partially cut away and with the wrapper partially opened, of a napkin to which the improvement of this invention is particularly applicable;

Figure 2 is a perspective view of a sanitary napkin of the type shown in Figure 1, incorporating the present invention;

Figure 3 is a cross-sectional view, taken along the line of 33 of Figure 2, and

Figure 4 is an enlarged cross-sectional view similar to Figure 3 but with the napkin in folded position ready for application to the body.

Referring first to Figure 1, it is seen that a representative sanitary napkin includes a wrapper l of gauze or similar material, and a body portion comprising outer plies 2a and 2b of creped tissue paper, intermediate plies 3a and 3b of fluffy cellulose pulp, an intermediate layer 4 of cotton linters or the like providing bulk, softness and additional absorptive capacity, and a second intermediate ply 5 of waxed tissue paper or the like to serve as a baflle. Other conventional elements may be included as desired. and the elements may be arranged in various ways, but such elements are not here disclosed in detail since they are not material to the invention. Wrapper 1 is folded around the body of the sanitary pad with the resulting seam as at 6 along one side or surface of the pad, and with extended ends 9 by which the napkin is pinned or otherwise fastened to a belt or the like for maintenance in position against the body.

It is obvious that the napkin of Figure 1 has a greater thickness of absorptive material below baflle 5 than it has above that battle, there being three layers 2a. 3a and 4 below and only two layers 2b and 3b above baflle 5. Con sequently, the napkin as shown is particulary adapted to have the surface 7 of the napkin as seen in Figure 1 turned upwardly and applied against the portion of the body from which the menstrual flow discharges, rather than the surface 8. Consistent with this is the fact that the seam s of wrapper 1 also appears or is exposed at the surface or side 3 of the napkin particularly adapted to be worn away from the body (to obviate any tendency of the seam edge to irritate sensitive body portions).

Figure 2 shows the incorporation of the present invention in a napkin of the type shown in Figure l. The napkin has a line of weakness in one main face or side, here illustrated as a score line 10 impressed into the side or face 8 of the napkin which is particularly adapted to be worn away from the body. Referring also to Figure 3, it is seen that this score line provides an actual impression or line of indentation into the surface 8 and the material of the napkin immediately adjacent surface 8. This line of Weakness or indentation preferably is provided by a scoring rule, rod or Wheel which may be pressed against and into the surface or side 8 of the napkin. sufl'iciently to upset the fibers in the material against which it directly impinges and the material most closely adjacent thereto. The scoring means exerts a force which distorts the layer or layers immediately adjacent the line of contact, the distortion of the layer or layers and upsetting of the fibers being progressively less as the distance from the line of contact increases and preferably appearing not at all in the part of the napkin opposite to the scored side, as shown in Figure 3. If the line of embossing or indentation is too deep the body fluid tends to strike through that portion of the pad. As is evident, sanitary napkins as described above and illustrated in Figs. 1 and 2 are, as manufactured and packaged, of generally planiform configuration, since at least the main absorbent portion there of is essentially a flat pad. Such a napkin is, however, caused to assume a quite different configuration when worn. For optimum conditions of use, it is desirable that the napkin be readily foldable in U-configuration substantially along a longitude extending center line.

Referring particularly to Figure 3, it will be clear that a compression force applied to approximately the centers of the side edges of the napkin and parallel to the planes of the plies will, due to the weakening provided by line 10, produce a folding of the napkin about line 10, with the result shown in Figure 4. The tendency to fold in this manner results both from a weakening of the material adjacent surface 8 and the reduction in the cross-section of the force-resisting material in the vicinity of surface 8. This folding produces a U-shaped cross-section in the napkin, with the more absorbent part of the napkin at the exterior of the base of the U (the uppermost part as seen in Figure 4), and with the impression line and the seam 6 essentially buried within the fold of the U. Thus, the ideal conformation of the napkin both as to comfort and absorbency, naturally results from the construction provided. It is obvious that the pressure of the line of weakness will promote maintenance of the shape shown in Figure 4 throughout the time the napkin is worn, with consequent decreased chance that the napkin will be displaced from the optimum position against the body.

It should also be noted that sanitary pads are frequently applied in the dark and under such conditions it is difficult to detect the wrapper seam or gauze fold side of a pad of conventional design. However, with this invention the indentation in the one surface of the pad quickly identifies that side of the pad to be worn away from the body.

The wrapper 1 of most sanitary napkins incorporates a small amount of an adhesive which is somewhat thermosensitive. Consequently, if the impression-forming means, whether a rule, rod, wheel or press, be heated,

there will result a tacking together of the edges of the wrapper at the impression line 10 adjacent seam 6 and a tacking of the wrapper to the main napkin body. This will effectively eliminate any opportunity for the main body of the napkin to escape the wrapper. Further, if the time of contact between napkin and heated impressionforming means is sufficient, under certain moisture conditions of the napkin a more definite and permanent set of the impression may be obtained.

Numerous variations in the above-described embodiment will be apparent to those skilled in the art. For example, the impression line 10 might be interrupted or discontinuous without detracting from the effectiveness of the invention, or it might be formed of two parallel, closely spaced lines, or it might be impressed into the napkin before the wrapper 1 is applied. Accordingly, it is to be understood that the invention is to be limited only in accordance with the appended claims.

I claim:

1. A sanitary napkin of generally planar configuration comprising plural layers of fibrous absorbent material maintained in unitary assembly by an enclosing fluid permeable wrapper, the outermost wrapper-enclosed face of one layer providing the upper or body contacting side of the napkin, and an outermost wrapper enclosed face of another of said layers providing the lower face of the napkin during use, said lower face of said last mentioned layer being provided substantially centrally thereof with a longitudinally extending impress confined to said lowermost layer to aid transverse folding, said impress being defined by a longitudinally extending area of fiber compression and increased fiber density.

2. A sanitary napkin of generally planar configuration comprising plural layers of fibrous absorbent material maintained in unitary assembly by an enclosing fluid permeable wrapper, the outermost wrapper-enclosed face of one layer providing the upper or body contacting side of the napkin, and an outermost wrapper enclosed face of another of said layers providing the lower face of the nap kin during use, said lower face of said last mentioned layer being provided substantially centrally thereof with a longitudinally extending impress confined to said lowermost layer to aid transverse folding, said impress being defined by a single longitudinally extending area of fiber compression and increased fiber density.

References Cited in the file of this patent UNITED STATES PATENTS 1,081,724 De Smith Dec. 16, 1913 1,863,333 Heitmeyer June 14, 1932 1,974,578 Medotf Sept. 25, 1934 2,551,663 Fox May 8, 1951 2,600,576 Rickard et al June 17, 1952 2,682,875 Brown July 6, 1954 2,747,575 Mercer May 29, 1956 FOREIGN PATENTS 580,018 Germany Jan. 31, 1934 1,090,981 France Oct. 27, 1954

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